Both behavioral and electrophysiological studies of the visual process of the cat will be made to assess effects of restrictions in the visual environment during early development. Animals will be reared under stroboscopic illumination, in appropriate control conditions, or under normal laboratory conditions. Microelectrode recordings will be made from the visual cortex and single units will be studied for selectivity to orientation, movement and direction of motion of the stimulus. Behavioral studies will be made to determine the threshold velocity for detection of motion, and the threshold difference in orientation of moving patterns which can be discriminated. Measurements of flicker fusion frequency and visual acuity and observations of depth discrimination will also be made.